JP2007226242A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of more improving side visibility by preventing pixels from having different color coordinate values between lateral and front directions of a screen. <P>SOLUTION: A display panel of the display device 100 has a pair of pixels (a high pixel and a low pixel) that are formed in the same pixel area. A driving section holds data corresponding to a high pixel gamma curve relatively high in gradation for a specified gradation and a low pixel gamma curve relatively low by R, G, and B. The driving section generates a second image signal by using data that corresponds to the high pixel gamma curve and outputs it to the high pixel, and generates a third image signal by using data that corresponds to the low pixel gamma curve and outputs it to the low pixel based upon a first image signal externally received. Low pixel gamma curves are the same among R, G, and B, especially, in a low luminance area. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device, and more particularly to a display device including regions having different luminances in the same pixel.

  A liquid crystal display (LCD) displays an image by applying a voltage to a liquid crystal layer sandwiched between two substrates to align liquid crystal molecules in a predetermined direction and controlling its light transmittance. . Since the degree of light shielding by the liquid crystal molecules in the liquid crystal layer depends on the direction, the liquid crystal display device generally has a narrower viewing angle than other display devices.

  As means for enlarging the viewing angle, a vertically aligned (VA) mode liquid crystal display device has been developed. In the VA mode liquid crystal display device, each substrate is subjected to vertical alignment treatment. Further, a liquid crystal layer having a negative dielectric anisotropy is sealed between the two substrates. Thereby, the liquid crystal molecules of the liquid crystal layer exhibit the property of vertical alignment. In a pixel in a state where a voltage is not applied between the two substrates, the liquid crystal molecules are aligned in a substantially vertical direction with respect to the surface of each substrate, and thus the luminance of the pixel indicates black. In a pixel in a state where a voltage is applied between the two substrates, the liquid crystal molecules are inclined obliquely from a direction substantially perpendicular to the surface of each substrate, so that the luminance of the pixel increases. The higher the voltage applied between the two substrates, the more the liquid crystal molecules are tilted, so the luminance of the pixel is higher. When the liquid crystal molecules are aligned in a substantially horizontal direction with respect to the surface of each substrate, the luminance of the pixel shows white.

  In general, a medium-sized / small-sized liquid crystal display device has a particularly narrow viewing angle, and the gradation of each pixel is easily inverted on the side. As means for solving this problem, these liquid crystal display devices particularly adopt a PVA (Patterned Vertically Alignment) structure. In the PVA mode liquid crystal display device, each of the common electrode layer of the color filter substrate and the pixel electrode layer of the array substrate is patterned, whereby each pixel region is divided into a plurality of domains. Since the orientation direction of the liquid crystal molecules is different for each domain, the viewing angle is enlarged, and in particular, gradation inversion is suppressed.

  In recent years, in order to further improve the viewing angle, a super PVA (hereinafter referred to as SPVA) mode liquid crystal display device has been developed. In the SPVA mode liquid crystal display device, a main pixel and a sub-pixel are formed in one pixel region. Further, since the applied voltage is different between the main pixel and the sub-pixel with respect to the gradation of the designated pixel, the luminance is different. Hereinafter, the relatively high brightness is called a high pixel, and the low brightness is called a low pixel. In the SPVA mode liquid crystal display device, not only the orientation direction of the liquid crystal molecules but also the distribution characteristics (particularly, the relationship between the specified gradation and the actual orientation state) differ between the high pixel and the low pixel. Not only is the corner enlarged, but the side visibility is improved.

However, in a conventional SPVA mode liquid crystal display device, a phenomenon in which the color changes to yellow (yellowing phenomenon) generally occurs as the screen viewing direction is shifted from the front to the side. That is, as shown below, the color coordinate value at each gradation shifts to the yellow side from the front direction on the side.
FIG. 1 is a graph showing the relationship between the gradation and the color coordinate value in the front direction. FIG. 2 is a graph showing the relationship between gradation and color coordinate values on the side.
As shown in FIG. 1, the x color coordinate value observed in the front direction changes in the range of 0.265 to 0.28, and the y color coordinate value observed in the front direction is 0.23 to 0.288, depending on the specified gradation. It varies in the range. Typical color coordinate values are shown in Table 1.

  As shown in FIG. 2, the x color coordinate value observed on the side changes in the range of 0.27 to 0.29 and the y color coordinate value changes in the range of 0.26 to 0.30 according to the designated gradation. Representative color coordinate values are shown in Table 2.

  As is apparent from comparison between Table 1 and Table 2, for each gradation, the color coordinate value in the side is generally higher than the color coordinate value in the front direction. This indicates that more yellow component is observed on the side than in the front direction.

The reason why the color coordinate values are different between the front direction and the side direction is that the RGB gamma curves are different between the high pixel and the low pixel included in the same pixel region.
FIG. 3 is a graph showing two types of gamma curve groups used in a conventional SPVA mode liquid crystal display device. FIG. 4 is an enlarged view of the gamma curve group shown in FIG. 3 in a region where the transmittance is 0.1 or less. In FIGS. 3 and 4, the RGB gamma curve group A having a relatively high transmittance (luminance) for each gradation is for a high pixel, and the relatively low RGB gamma curve group B is for a low pixel.

In the conventional SPVA mode liquid crystal display device, as shown in FIG. 3 and FIG. 4, the gamma curve group B for the low pixel is in the low luminance region (that is, the pixel transmittance (luminance) is very close to the lower limit 0. Also in the region below the vicinity of the tone value 511), it differs between RGB. When the screen is observed from the side, the pixel transmittance (luminance) by the low pixel gamma curve group B in this low luminance region is dominant. Therefore, a difference in gamma curve between RGB as shown in FIG. 4 induces a color change of the pixel on the side of the screen.
The present invention focuses on this point. An object of the present invention is to provide a display device capable of further improving the side visibility by preventing a change in the color coordinate value of a pixel between the side of the screen and the front direction.

  The display device according to the present invention includes a display panel and a driving unit. The display panel includes a pair of pixels formed in the same pixel region, that is, a high pixel and a low pixel. The driving unit converts data corresponding to a gamma curve (hereinafter referred to as a high pixel gamma curve) and a relatively low gamma curve (hereinafter referred to as a low pixel gamma curve) having a relatively high luminance with respect to a specified gradation into RGB. Hold every time. The driving unit further generates a second image signal using data corresponding to the high pixel gamma curve based on the first image signal provided from the outside, outputs the second image signal to the high pixel, and data corresponding to the low pixel gamma curve. Is used to generate a third image signal and output it to the low pixel. In particular, in a region where the luminance is lower than a predetermined value (hereinafter referred to as a low luminance region), the low pixel gamma curve is the same between RGB. That is, in the low luminance region, the luminance of each RGB low pixel matches for each gradation value designated from the outside. Here, in the low luminance region, the luminance of the low pixel is preferably about 10% or less of the maximum value.

  Preferably, the driving unit includes a timing control unit and a data driving unit. The timing controller preferably generates first image data from the first image signal using data corresponding to the high pixel gamma curve and uses the data corresponding to the low pixel gamma curve to generate the second image from the first image signal. Generate data. The data driver converts the first image data into a second image signal, and converts the second image data into a third image signal.

  In addition, the timing control unit generates image data from the first image signal, and the data driving unit converts the image data into the second image signal by correction using data corresponding to the high pixel gamma curve. The image data may be converted into a third image signal by correction using data corresponding to the curve. In that case, preferably, the drive unit further includes a holding unit and a switching unit. The holding unit holds data corresponding to each of the high pixel gamma curve and the low pixel gamma curve for each RGB. The switching unit outputs the data held by the holding unit to the data driving unit according to the timing control unit.

  The display device according to the present invention divides each pixel region into a pair of a high pixel and a low pixel, and individually adjusts the luminance of each pixel using different gamma curves. In particular, the brightness of the high pixel is set higher than the brightness of the low pixel for each designated gradation. Thereby, the viewing angle of the screen is wide and the side visibility is high. The display device according to the present invention further matches the RGB low pixel gamma curves in the low luminance region. Thereby, on the side of the screen, the color coordinate value of the pixel at each gradation is maintained substantially equal to the color coordinate value in the front direction, and particularly an increase in yellow component is suppressed. As a result, the side visibility is further improved.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 5 is a block diagram of a liquid crystal display device according to an embodiment of the present invention. As shown in FIG. 5, the liquid crystal display device 100 includes a liquid crystal display panel 110, a holding unit 120, a timing control unit 130, a gate driving unit 140, and a data driving unit 150.

  The liquid crystal display panel 110 includes q gate lines and p data lines. The gate line and the data line delimit each pixel region. High pixels and low pixels are formed in each pixel region. The high pixel includes a first switching element Th, a first liquid crystal capacitor Clch, and a first storage capacitor Csth. In the high pixel of the nth row (n = 1, 2,..., q), the first switching element Th is connected to the nth gate line and the odd numbered data line. The first liquid crystal capacitor Clch and the first storage capacitor Csth are connected to the first switching element Th. The low pixel includes a second switching element Tl, a second liquid crystal capacitor Clcl, and a second storage capacitor Cstl. In the row pixel of the nth row (n = 1, 2,..., q), the second switching element Tl is connected to the (n + 1) th gate line and the even-numbered data line. The second liquid crystal capacitor CLcl and the second storage capacitor Cstl are connected to the second switching element Tl.

  The holding unit 120 preferably includes a first holding unit 122 and a second holding unit 124. The first holding unit 122 holds data corresponding to a gamma curve for a high pixel (hereinafter referred to as a high pixel gamma curve) for each RGB. The second holding unit 124 holds, for each RGB, data corresponding to a gamma curve for a low pixel (hereinafter referred to as a low pixel gamma curve; see curve group B shown in FIG. 6). Preferably, in the first holding unit 122, data corresponding to the red (R) gamma curve is held as the first lookup table LUT-R, and data corresponding to the green (G) gamma curve is stored in the second lookup table. Data is stored as a table LUT-G, and data corresponding to a blue (B) gamma curve is stored as a third lookup table LUT-B. On the other hand, in the second holding unit 124, the data corresponding to the red (R) gamma curve is held as the fourth lookup table LUT-R, and the data corresponding to the green (G) gamma curve is stored in the fifth lookup table. The data corresponding to the blue (B) gamma curve is held as the LUT-G, and is held as the sixth lookup table LUT-B. In particular, the look-up table held in the second holding unit 124 indicates that “each RGB low pixel gamma curve is in a low luminance region (that is, the pixel transmittance (brightness) is close to 0, the vicinity of the gradation value 511 or less. It is the same in the area). As a result, in the low luminance region, the transmittance (luminance) of the low pixels is the same between RGB as shown in FIG. Here, in the low luminance region, as shown in FIG. 6, the transmittance of the low pixel is preferably about 0.1 or less, that is, the luminance of the low pixel is about 10% or less of the maximum value.

  The timing control unit 130 receives the first image signals R, G, and B and the first timing signal S1 from an external graphic controller (not shown). The first timing signal S1 includes a horizontal synchronization signal, a vertical synchronization signal, a data enable signal, and a main clock. The timing control unit 130 further generates first image data RH, GH, BH from the first image signals R, G, B using data corresponding to the high pixel gamma curve held in the first holding unit 122, The second image data RL, GL, and BL are generated from the first image signals R, G, and B using data corresponding to the low pixel gamma curve held in the second holding unit 124. The timing controller 130 subsequently generates a second timing signal S2 and outputs the second timing signal S2 to the data driver 150 together with the first image data RH, GH, BH or the second image data RL, GL, BL. The second timing signal S2 includes a load signal and a horizontal start signal. In parallel with these operations, the timing controller 130 generates a third timing signal S3 and outputs it to the gate driver 140. The third timing signal S3 includes a gate clock and a vertical start signal.

The gate driver 140 sequentially outputs gate signals G1, G2,..., Gq−1, Gq to q gate lines in accordance with the third timing signal S3.
The data driver 150 converts the first image data RH, GH, BH or the second image data RL, GL, BL into data voltages D1, D2,..., Dp according to the second timing signal S2. Data voltages D1, D3,... Converted from the first image data RH, GH, BH are output to odd-numbered data lines, and data voltages D2, D4, converted from the second image data RL, GL, BL are output. ... are output to even-numbered data lines. Preferably, the polarity of the data voltage with respect to the common voltage Vcom is inverted between two adjacent data lines or between two consecutive frames.

  The liquid crystal display device 100 preferably further includes a power supply unit (not shown). In that case, the timing control unit 130 generates another timing signal (not shown). The power supply unit provides a gate-on voltage and a gate-off voltage to the gate driving unit 140 according to the timing signal. The power supply unit further applies a common voltage Vcom to the liquid crystal capacitors Clch and Clcl of the liquid crystal display panel 110 in synchronization with the gate signals G1, G2,..., Gq−1, Gq.

  Using the above configuration, the liquid crystal display device 100 individually adjusts the transmittance of each of the high pixel and the low pixel included in each pixel region according to different gamma curves. In particular, the brightness of the high pixel is set higher than the brightness of the low pixel for each designated gradation. Thereby, the viewing angle of the screen is wide and the side visibility is high. The liquid crystal display device 100 further matches the data corresponding to the RGB low pixel gamma curves in the low luminance region. Thereby, as shown below, the x and y color coordinate values are lower on the side of the screen than those of the conventional display device. As a result, the yellowing phenomenon on the side is prevented.

  FIG. 7 is a graph showing the relationship between the designated gradation value and the color coordinate value observed on the side of the screen for the pixel of the liquid crystal display device 100 according to the embodiment of the present invention. As shown in Figure 7, according to the specified gradation, the x color coordinate value observed on the side changes in the range of 0.278 to 0.294, and the y color coordinate value changes in the range of 0.26 to 0.293. To do. Representative color coordinate values are shown in Table 3.

  As is clear from the comparison between FIG. 2 and FIG. 7 and the comparison between Table 2 and Table 3, in the liquid crystal display device 100 according to the embodiment of the present invention, x observed from the side than the conventional liquid crystal display device, All y color coordinate values are generally low. That is, the yellowing phenomenon on the side (yellowish) is suppressed.

Hereinafter, the generation process of data to be held in each lookup table will be described with reference to FIGS.
The standard gamma curve shown in FIG. 8 shows the specified gradation and the transmittance (brightness) of the pixel when the same voltage is applied to the high pixel and the low pixel included in the same pixel region. ). Note that the standard gamma curve is generally different between RGB in practice. In the generation of the above lookup table, first, a data pair of gradation and transmittance (luminance) is extracted from the standard gamma curve shown in FIG. Here, the bit representing each gradation value is expanded by dithering. For example, if the gradation value is represented by 8 bits (ie, 0 to 255), dithering can be further divided into 8 bits to further subdivide the gradation values 90 and 91 into 90.25, 90.5, and 90.75. Is expanded to 10 bits. As a result, the 8-bit gradation values 90, 90.25, 90.5, 90.75, and 91 are sequentially converted into 10-bit gradation values 360, 361, 362, 363, and 364. In FIG. 6, since the gradation value is represented by 10 bits, the central gradation value 511 corresponds to the 8-bit gradation value 127.75.

  Next, the target low pixel gamma curve (B-target) shown in FIG. 9 is set so as to optimize the side visibility. Thereafter, a target high pixel gamma curve (A-target) is set using the target low pixel gamma curve (B-target) and the target gamma curve in the front direction (front-target).

  Subsequently, the transmittance (luminance) is extracted for each designated gradation from each of the target high pixel gamma curve and low pixel gamma curve. In addition, a pair of transmittance (luminance) that most closely approximates each extracted transmittance (luminance) and the corresponding tone value of the data obtained from the standard gamma curve (bit extended) It is selected from the inside. The relationship between the gradation value selected in this way and the designated original gradation value is held by the holding unit 120 in the form of a lookup table.

  For example, when the specified (8-bit) gradation value is 128, the transmittance extracted from the high pixel gamma curve is very close to 0.6 (see point PH in FIG. 10). On the other hand, in the data obtained from the standard gamma curve, the gradation value corresponding to the transmittance closest to the extracted transmittance (≈0.6) is 205.25 (821 for 10 bits) (point in FIG. 10). See QH). Therefore, in the lookup table to be obtained from the high pixel gamma curve, 821 is recorded as the gradation value for the designated gradation value 128.

  When the specified (8-bit) tone value is 128, the transmittance extracted from the low pixel gamma curve is very close to 0.04 (see point PL in FIG. 10). On the other hand, in the data obtained from the standard gamma curve, the gradation value corresponding to the transmittance closest to the extracted transmittance (≈0.04) is 66 (264 for 10 bits) (point in FIG. 10). See QL). Therefore, in the lookup table to be obtained from the low pixel gamma curve, 264 is recorded as the gradation value for the designated gradation value 128.

The above operation is executed for each RGB. Here, in the low luminance region, the target low pixel gamma curve is matched between RGB. Preferably, a region where the transmittance of the low pixel is about 0.1 or less, that is, the region where the luminance of the low pixel is about 10% or less of the maximum value is set as the low luminance region (see FIG. 6). Thus, the first to sixth look-up tables are set and held by the holding units 122 and 124.
FIG. 11 shows an example of the lookup table set in this way. In FIG. 11, for each of the specified (8-bit) gradation values 0 to 255, the (10-bit) gradation value (A in red) and the fourth lookup recorded in the first lookup table. Tone value (10-bit) recorded in the table (B for red), Tone value (10-bit) recorded in the second lookup table (A for green), recorded in the fifth lookup table (10-bit) gradation value (green B), (10-bit) gradation value (blue A) recorded in the third lookup table, and recorded in the sixth lookup table (10 The gradation value (blue B) is shown. That is, for each of RGB, the data obtained from the high pixel gamma curve is shown in column A, and the data obtained from the low pixel gamma curve is shown in column B. In particular, the RGB gradation values for the low pixels correspond to the same transmittance (luminance) of the RGB low pixels for each designated gradation value in the low gradation region (FIG. 6). reference).

  FIG. 12 is a block diagram of a liquid crystal display device according to another embodiment of the present invention. As shown in FIG. 12, the liquid crystal display device 200 includes a liquid crystal display panel 210, a first holding unit 220, a second holding unit 230, a timing control unit 250, a switching unit 260, a first gate driving unit 270, A second gate driver 280 and a data driver 290 are included.

  The liquid crystal display panel 210 includes q gate lines and p data lines. The gate line and the data line delimit each pixel region. High pixels and low pixels are formed in each pixel region. The high pixel includes a first switching element Th, a first liquid crystal capacitor Clch, and a first storage capacitor Csth. The first switching element Th is connected to the odd-numbered gate line and one of the data lines. The first liquid crystal capacitor CLch and the first storage capacitor Csth are connected to the first switching element Th. The low pixel includes a second switching element Tl, a second liquid crystal capacitor Clcl, and a second storage capacitor Cstl. The second switching element Tl is connected to the even-numbered gate line and one of the data lines. In each pixel region, the first switching element Th and the second switching element Tl are connected to the same data line. The second liquid crystal capacitor Clcl and the second storage capacitor Cstl are connected to the second switching element Tl.

  The first holding unit 220 holds data corresponding to the high pixel gamma curve for each RGB. The second holding unit 230 holds data corresponding to the low pixel gamma curve for each RGB. Each data is preferably held in the form of a look-up table, similar to the holding unit shown in FIG. In particular, the lookup table held in the second holding unit 230 is similar to the lookup table held in the second holding unit 124 shown in FIG. It is the same. As a result, in the low luminance region, the transmittance (luminance) of the low pixels is the same between RGB as shown in FIG. Here, in the low luminance region, as shown in FIG. 6, the transmittance of the low pixel is preferably about 0.1 or less, that is, the luminance of the low pixel is about 10% or less of the maximum value.

  Similar to the timing control unit shown in FIG. 5, the timing control unit 250 receives the first image signals R, G, B and the first timing signal S1 from an external graphic controller (not shown). The timing controller 250 further generates a set of image data R ′, G ′, and B ′ from the first image signals R, G, and B, unlike the timing controller shown in FIG. 5. Next, the timing control unit 250 generates the second timing signal S2 and outputs the second timing signal S2 to the data driving unit 290 together with the image data R ′, G ′, and B ′ similarly to the timing control unit shown in FIG. In parallel with these operations, the timing controller 250 generates a pair of the third timing signal S31 and the fourth timing signal S32 and outputs them to the first gate driver 270 and the second gate driver 280, respectively. The third timing signal S31 and the fourth timing signal S32 each include a gate clock and a vertical start signal.

  The switching unit 260 alternates data corresponding to the high pixel gamma curve held by the first holding unit 220 and data corresponding to the low pixel gamma curve held by the second holding unit 230 according to the timing control unit 250. The data is output to the data driver 290.

  The first gate driver 270 sequentially outputs gate signals G1, G3,..., Gq-3, Gq−1 to odd-numbered gate lines according to the third timing signal S31. The second gate driver 280 sequentially outputs the gate signals G2, G4,..., Gq-2, Gq to the even-numbered gate lines according to the fourth timing signal S32. Here, the pair of the third timing signal S31 and the fourth timing signal S32 is adjusted so that the gate signals between the two gate driving units 270 and 280 show the gate-on voltage in different periods.

  The data driver 290 alternately receives data corresponding to the high pixel gamma curve and the low pixel gamma curve from the switching unit 260 according to the second timing signal S2. The data driver 290 further corrects the image data R ′, G ′, and B ′ provided from the timing controller 250 using the received data. Subsequently, the data driver 290 converts the corrected image data R ′, G ′, B ′ into data voltages D1, D2,..., Dp. The data voltages D1, D2,..., Dp are output to each of the p data lines of the liquid crystal display panel 210. In particular, the data voltage obtained by the correction using the data corresponding to the high pixel gamma curve is output during the period in which the odd-numbered gate lines are activated by the first gate driver 270, and the low pixel gamma curve is output. The data voltage obtained by the correction using the corresponding data is output by the second gate driver 280 during the period when the even-numbered gate line is activated. Preferably, the polarity of the data voltages D1, D2,..., Dp with respect to the common voltage Vcom is inverted between two adjacent data lines or between two consecutive frames.

  The liquid crystal display device 200 preferably further includes a power supply unit (not shown). In that case, the timing controller 250 generates another timing signal (not shown). The power supply unit provides a gate-on voltage and a gate-off voltage to the first gate driving unit 270 and the second gate driving unit 280 according to the timing signal. The power supply unit further applies a common voltage Vcom to the liquid crystal capacitors Clch and Clcl of the liquid crystal display panel 210 in synchronization with the gate signals G1, G2,..., Gq−1, Gq.

  The preferred embodiments of the present invention have been described in detail above. However, the embodiments of the present invention are not limited to the above. Those skilled in the art to which the present invention pertains can modify or change the above-described embodiments without departing from the spirit and spirit of the present invention.

The graph which shows the relationship between the designated gradation value and the color coordinate value observed in the front direction of a screen about the pixel of the conventional SPVA mode liquid crystal display device A graph showing a relationship between a designated gradation value and a color coordinate value observed on the side of the screen for a pixel of a conventional SPVA mode liquid crystal display device Graph showing two types of gamma curve groups used in a conventional SPVA mode liquid crystal display device Fig. 3 is an enlarged view of the gamma curve group shown in Fig. 3 in the region where the transmittance is 0.1 or less. 1 is a block diagram of a liquid crystal display device according to an embodiment of the present invention. The figure which expanded and showed the gamma curve group utilized by the liquid crystal display device by one Example of this invention in the area | region where the transmittance | permeability is 0.1 or less. FIG. 5 is a graph showing a relationship between a designated gradation value and a color coordinate value observed on the side of the screen for a pixel of a liquid crystal display device according to an embodiment of the present invention; 6 is a graph showing a standard gamma curve used in a liquid crystal display device according to an embodiment of the present invention. 6 is a graph showing a target high pixel gamma curve, a low pixel gamma curve, and a gamma curve in a front direction of a screen, which are used in a liquid crystal display device according to an embodiment of the present invention. A liquid crystal display device according to an embodiment of the present invention uses a target high pixel gamma curve, low pixel gamma curve, and standard gamma curve to specify a specified gradation value and a gradation to be recorded in a lookup table. Graph showing the relationship between values Table showing an example of the lookup table set from the relationship shown in FIG. Block diagram of a liquid crystal display device according to another embodiment of the present invention.

Explanation of symbols

100, 200 LCD
110, 210 LCD panel
120 Holding part
122, 220 1st holding part
124, 230 Second holding part
130, 250 Timing controller
140, 270, 280 Gate drive
150, 290 Data driver
260 Timing controller

Claims (13)

A display panel including a pair of pixels (hereinafter, one is called a high pixel and the other is called a low pixel) formed in the same pixel region; and
Data corresponding to a relatively high gamma curve (hereinafter referred to as a high pixel gamma curve) and a relatively low gamma curve (hereinafter referred to as a low pixel gamma curve) for a specified gradation is stored for each RGB. The second image signal is generated using data corresponding to the high pixel gamma curve based on the first image signal provided from the outside and output to the high pixel, and the data corresponding to the low pixel gamma curve is output. A driving unit that generates a third image signal using the third image signal and outputs the third image signal to the low pixel;
A display device having
A display device in which the low pixel gamma curve is the same between RGB in a region where the luminance is lower than a predetermined value (hereinafter referred to as a low luminance region). The drive unit is
First image data is generated from the first image signal using data corresponding to the high pixel gamma curve, and second image data is generated from the first image signal using data corresponding to the low pixel gamma curve. Timing control unit, and
A data driver for converting the first image data into the second image signal and converting the second image data into the third image signal;
The display device according to claim 1, comprising:   The display device according to claim 2, further comprising a holding unit that holds data corresponding to each of the high pixel gamma curve and the low pixel gamma curve for each of RGB.   The display device according to claim 2, wherein the display panel includes a gate line and a data line that divide the pixel region. The high pixel is
A first switching element connected to the gate line and the odd-numbered data line; and
A first liquid crystal capacitor coupled to the first switching element;
The display device according to claim 4, comprising: The low pixel is
A second switching element connected to a gate line different from the gate line connected to the first switching element and an even-numbered data line; and
A second liquid crystal capacitor coupled to the second switching element;
The display device according to claim 5, comprising: The drive unit is
A timing control unit for generating image data from the first image signal; and
The image data is converted to the second image signal by correction using data corresponding to the high pixel gamma curve, and the image data is converted to the third image signal by correction using data corresponding to the low pixel gamma curve. Data driver to convert to,
The display device according to claim 1, comprising: The drive unit is
A holding unit for holding data corresponding to each of the high pixel gamma curve and the low pixel gamma curve for each RGB; and
In accordance with the timing control unit, a switching unit that outputs the data held by the holding unit to the data driving unit,
The display device according to claim 7, further comprising:   The display device according to claim 8, wherein the data driving unit corrects the image data using data held by the holding unit. The display panel includes a gate line and a data line that divide the pixel region,
The high pixel is
A first switching element connected to the odd-numbered gate line and the data line; and
A first liquid crystal capacitor coupled to the first switching element;
including,
The display device according to claim 7. The low pixel is
A second switching element connected to the even-numbered gate line and the data line; and
A second liquid crystal capacitor coupled to the second switching element;
The display device according to claim 10, comprising: The drive unit is
A first holding unit for holding data corresponding to the high pixel gamma curve for each of RGB;
A second holding unit for holding data corresponding to the low pixel gamma curve for each RGB, and
A switching unit that outputs either the data held by the first holding unit and the data held by the second holding unit to the data driving unit according to the timing control unit;
Further including
The data driver converts the image data into the second image signal by correction using the data held by the first holding unit, and the correction by using the data held by the second holding unit. Converting image data into the third image signal;
The display device according to claim 7.   The display device according to claim 1, wherein in the low luminance region of the low pixel gamma curve, the luminance of the low pixel is about 10% or less of the maximum value.

Images